In the related art, as an example of a liquid ejecting apparatus, an ink jet printer is known. In the ink jet printer, it is possible to perform printing on a printing medium by discharging ink which is an example of a liquid to the printing medium such as a printing sheet from an ejecting head. In such a liquid ejecting apparatus, in the related art, a configuration in which the ink stored in a tank which is an example of a liquid container is supplied to an ejecting head (for example, refer to PTL 1). In the tank, an injecting port is provided. A user can inject the ink to the tank from the injecting port. Note that, in the following description, a configuration in which a liquid container such as the tank is added to the liquid ejecting apparatus such as an ink jet printer will be expressed as a liquid ejecting system in some cases.